Sawmill setworks



H. F. BIEDERMANN.

SAWMILL SETWORKS.

' APPLICATION FILED APR. 25, 1921. mm m Patented Apr. 11, 1922.

2 SHEETS-SHEET l- H. F. BIEDERMANN.

SAWMILL SETWQRKS.

APPLICATION FILED APR.25, 1921.

1,412,?970 Patented Apr. 11, 1922.

2 SHEETS-SHEET 2.

HUGO F. BIEDERMANN, 0F TUSCALOOSA, ALABAMA.

SAWMILL SETWORKS.

misses.

Application filed April 25, 1921.

To all whom it may concern:

Be it known that I, HUGO F. BIEDERMANN, a citizen of the United States, residing at Tuscaloosa, in the county of Tuscaloosa and State of Alabama, have invented certain new and useful Improvements in Sawmill Setworks, of which the following is a specification.

The present invention relates to improvements in sawmill set-works. In the setworks of ordinary sawmills it is usual to provide means for collectively and individually operating the setting-knees, the latter being disposed in series on the log-carriage. Ordinarily the setting-knees are each slidably fitted to a rack-bar, which in turn is slidable in suitable guide-ways, so as to move on the carriage, and with the rack-bars of the setting-knees are arranged to mesh pinions on the set-shaft, which may be operated to simultaneously advance all the knees to a desired position, the retraction or backward movement of the knees being simultaneously effected by a strong torsion spring. The

means for individually adjusting the settingknees operate independently of the set-shaft mechanism, which includes the rack and pinion described,- each individual knee-adjusting device comprising a lever, fulcrumed on a segment which is attached to and forms a part of the setting-knee, said lever having its lower end connected by a link to the top side of the set-works rack. By reason of the loose connections between each setting-lever and the set-works rack and between the latter and the pinion on the set-shaft, there is a certain amount of lost motion at such loose connections. There is also a certain amount of lost motion in the keyed connection of the pinion to the set-shaft and in the set-shaft bearings. This lost motion increases as the parts wear, due to friction in the use of the set-works. Usually the torsion spring surrounds and is operatively connected to the set-shaft and as the knees are advanced the tension of the spring increases but ithas no tendency to take up the lost motion in the connections. It is frequently the case that the saw swerves somewhat from its path and draws on the log, so that one part of the latter is a little in advance of the other, which movement is permitted by the lost motion in the connections and which is disadvantageous because it results in variations in the thickness of the lumber.

It is an object of the present invention to Specification of Letters Patent.

Patented Apr. 3L1, 1922.

Serial No. 464,079.

provide improved means for retracting or receding the setting-knees operatively connected thereto in such manner as to exert sufiic ent tension thereon to take up lost motion in the connections and suflicient to compensate for swerving of the saw whatever the position of adjustment of the knees on the rack bars, and thereby prevent any knee from being drawn forward under the action of the saw, thus obviating irregular sawing of the lumber.

Another object of the invention is to provide an improved receding means of the character described which will exert a substantially constant tension on the setting knee as the latter is advancedstep by step by the set-shaft.

With these and other objects in view, which will more fully appear as the description proceeds, the invention consists in certain constructions and arrangements of parts, the novel features thereof being pointed out in the appended claims.

F or a full disclosure of the invention reference is to be had to the following description and accompanying drawings in which Figure l is a transverse sectional view through a log-carriage and a set-works mechanism equipped with may improved means for receding the setting knees and overcoming the lost motion in the connections.

Figure 2 is a plan view showing a settingknee and its receding mechanism.

Figure 3 is a detail view showing certain elements of the setting mechanism.

' Figure 4 is a fragmentary view showing a modification of the connection of the setting-knee to the sliding rack.

Corresponding and like parts are referred to in the following description and indicated in all of the views of the drawings by like crumed on the setting-knee at 5 is a lever 8 equipped with a sliding latch 7 adapted to engage any of the notches in the segment.

The lower end of the lever is connected to the sliding rack C by a link 8 either in the manner shown in Figure 1 or as shown in Figure 4-. By means of the lever 6 and its link connection 8 the setting-knee may be adjusted on its rack and held in adjusted position by the latch 7.

A log-carriage is provided with a series of setting-knees whichare advanced step by step by means of a set-shaft and the pinions thereon meshing with the racks of the setting-knees. Usually the set-shaft is sur rounded by a torsion spring which is put under tension as the set-shaft is turned to advance the setting-knees. A pawl and ratchet means is associated with the setshaft to latch it against reverse rotation. Means is provided whereby the pawl may be tripped at any time whereupon the torsion spring will rotate the set-shaft to recede all of the setting-knees to initial position. Since the means for operating the set-shaft and for latching it against reverse rotation is old, and forms no part of the present invention, such means is not illustrated in the drawings. V

In the present construction the torsion spring on the-set-shaft is omitted and for returning the setting-knee'to initial position a shaft 9 is arranged in rear thereof on the log-carriage and parallel to the set-shaft. Surrounding the shaft 9 is a torsion spring 10 having one end thereof fixed to the shaft and the other end secured to a frusto-conical member 11 journaled for rotation on the shaft; The member 11 is provided with a spiral groove 12. Secured to the frustoconical member 11 is one end of a cable 13 in the form of a chain. The other. end of the chain is attached to an extension 8 of the link 8 as shown in Figure 1 or to the lower end of the lever 6 as shown in Figure t. 'The torsion-spring operates to recede the setting-knee to initial position and in so doing winds the chain upon the frustoconical member 11. The end of the chain is attached to the frusto-conical member at the large end thereof and as the torsion spring rotates the member to recede the setting-knee the chain follows and occupies the spiral groove 12. An advantage of the spiral groove lies in the fact that as the chain winds on and 01f of the frusto-coriical member it cannot come in contact with itself and-cause the same to wea and the windings to become crossed. Since the chain is attached to the link connecting the lever 6 to the sliding rack C, as in Figure 1, or directly to the lever 6 as in Figure 4:, the tension of the torsion-springon the chain as the knee moves forward will take up any lost motion in the connections of the setting-knee to its rack, in the connections between the rack and pinion on the set-shaft, in the keyed connection of the pinion to'the set-shaft and in the set-shaft bearings. Obviously the tension of the torsion spring on the chain .when the knee is fully receded should be suficient totalre up this lost motion and to compensate for the swerving of the saw. The purpose of the frusto-conical member 11 is to cause the tension of the torsion spring exerted on the setting-knee through the chain to remain, substantially constantas the setting-knee is advanced step by step by the set-shaft. If the member 11 were cylindrical and the tension of the torsionspring was sufiicient when the setting-knee was fully receded to overcome the lost motion in the connections and to compensate for-the swerving of the saw, then as the setting-knee was advanced step by step the tension on the knee would gradually increase to an unnecessary amount as the settingknee was advanced.v On the other hand, if the tension on the chain were sufficient when the setting-knee was fully advanced it would be insuihcient when it was fully receded.

the provision of the frusto-conical member 11 it will be seen that when the settinglrnee is fully receded the chain is fully wound upon the member and is at'the small end thereof. The springj'at this time is exertingits least tension but the setting-knee is reacting against the tension of the spring through the chain. 7 This reactance operates through lever arm equal to the radius. of the small end of the frustoconical member. When the setting-knee is fully advanced the torsion'spring is exerting its greatest ten sion but the reactance of the setting-knee is exerted through a lever arm equal to the radius of the large end ofthe frusto-vconical memben it is quite evident that the frustoconical. member'may be so proportionedthat the effect of the spring on the setting-knee as it is. advanced step by step by the'set-shaf-t will remain substantially constant; Another advantage of the fru-sto-conical member'lies in, the fact that as the knee advances the chain travels towards the larger end' thereof thus being raised to clear the head block.

Having thus described my invention,

what I claim as new and desire to secure by Letters Patent is: I p

1., Ina sawmill set-works, the combination of a head-block, a set-shaft, arack slidably mountedon said head-block and geared to said set-shaft, a setting-knee slidably mounted. on said rack and adjustably connected thereto, and a spring actuated receding device operatively connected to said settingdrnee and adapted to exert'a substantiallyconstant tension on the latter as itis advanced step by step by the set-shaft sufficient totake up the lost motion in the connections.

' 21in a sawmlll set-works, the comb-ination of a head-block a set-shaft, a rack slidably mounted on said head-block and. geared to said set-shaft a setting-knee slidably mounted on said rack and adjust bly connected thereto, and means for receding said setting-knee and for exerting a substantially constant tension thereon as it is advanced step by step by said setshaft. com "ising a fixed shaft, a torsion spring surrounding said shaft and having one end secured thereto, a frusto-conical member rotatably mounted in said shaft and having the other end oi said spring secured. thereto and a cable \YOllIlCl upon said member and having its free end connected to said setting-knee.

3. In a sawmill set-Works, the combination of a head-block, a set-shaft, a rack slidably mounted on said head-block and geared to said Setshalt, a settingknee slidably mounted on said rack and adjustably connected thereto, and means for receding said setting-knee comprising a spring operutively connected to said. setting-knee in such manner as to exert a substantially constant tension thereon as it is advanced step by step by the set-shatt to compensate for lost motion.

4. In a sawmill set-Works, the combination of a head-block, a set-shaft, a rack slidably mounted on said head-block and geared to said set-shaft a setting-knee slidably nted on saie rack and adjustably con- 1 thereto and means for receding said setting-knee and for exerting a substantially constant tension thereon to cornpensate for lost motion as it is advanced step by step by said set-shaft comprisin a frusto-conical member mounted for rota-- tion, a torsion spring operatively connected to said shalt member for rotating it in one direction and opposing rotation thereof in the opposite direction, and a cable wound upon said member and having its free end connected to said setting-knee.

5w In a sawmill setwvorks, the combination or a head-block, a set-shaft, a rack slidably mounted on said hoad-blocl and geared to said set-shaft a setting-knee slidably mounted on said rack and adjustably con nected thereto, and means for receding said setting-knee and for exerting sutiicient tension thereon to compensate for lost motion as it is advanced step by step b y said setshaft comprising a trusto-conical member mounted for rotation and having a spiral groove therein, torsion spring operatively connected to said member tor rotating it in one direction and opposing rotation thereof in the opposite direction and a cable Wound upon said member and occupying said groove and having its free end connected to said settingknee.

6. In a sawmill set-Works, the combina tion of head-block, a setting-knee slidably mounted thereon, means for advancing said setting-knee on said head-block and means for receding said setting-knee, said means maintaining said settingdmee? under substantially uniform tension during its advancement.

7. In a sawmill set-Works, the combination of a head-block a setting-knee slidably mounted thereon means for advancing said setting-knee, and means for receding said setting-knee and for maintaining it under tension as it is advanced, including a tension compensating member adapted to maintain the tension on the settingdrnee substantially constant during its step by step advancement.

8. In a sawmill set-Works, the combina tion of a head-block, a setting-knee slidably mounted thereon, means for advancing said setting-knee and means for receding said setting-knee, including a frusto-conical drum operatively connected to said settingknee, and tension means connected to said drum the varying impelling force of which is equalized by said drum.

In testimony wh reof I affix my signature.

HUGO F. BIEDERMANN. 

